4C, avagy a kulcs a gyémántokhoz
Each diamond is unique and is a miracle of time, place and change. And each has specific qualities that establish its value.
Until the middle of the twentieth century, there was no agreed-upon standard by which diamonds could be judged. GIA created the first, and now globally accepted standard for describing diamonds:
- Color,
- Clarity,
- Cut
- and Carat Weight.
Today, the 4Cs of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world. The creation of the Diamond 4Cs meant two very important things: diamond quality could be communicated in a universal language, and diamond customers could now know exactly what they were about to purchase.
As creator of the Diamond 4Cs and the International Diamond Grading System™, GIA is not only a global authority, but the world’s trusted source for unbiased assessment.
Diamond Clarity Refers to the Absence of Inclusions and Blemishes
Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’ Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.
*GIA: Gemological Institute of America. HRD: Hoge Raad Voor Diamant (Diamond High Council). IGI: International Gemological Institute. AGS: American Gem Society Laboratories
| *HRD clarity classes | The size of inclusions and no blemishes** | *GIA clarity classes |
|---|---|---|
| Loupclean | No inclusions and no blemishes | F = flawless, If = internally flawless |
| VVS1, VVS2 | Very very small inclusion / slightly imperfect | VVS1, VVS2 |
| VS1, VS2 | Very small inclusion / slightly imperfect | VS1, VS2 |
| Si | Small inclusion / Slightly imperfect | Si1, Si2 |
| P. 1, P. 2, P. 3 | Piqué 1-3, Imperfect 1-3 | I 1, I 2, I 3 |
Diamond Color Actually Means Lack of Color
The diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. GIA’s D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to masterstones of established color value.
Many of these color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.
| *IDC, (HRD) | Antwerp | GIA, HRD | **Scand. D.N. - Swiss | |
|---|---|---|---|---|
| Colorless | Exceptional white + | 0+ | D | River |
| Colorless | Exceptional white | 0 | E | River |
| Colorless | Rare white + | 1+ | F | Top-wesselton |
| Near colorless | Rare white | 1 | G | Top-wesselton |
| Near colorless | White | 2 | H | Wesselton |
| Near colorless | Slightly tinted white | 3 | I | Top crystal |
| Near colorless | Slightly tinted white | 4 | J | Top crystal |
| Near colorless | Slightly tinted white | 4 | J | Crystal |
| Faint | Tinted white + | 5 | K | Crystal |
| Faint | Tinted white + | 5 | K | Top cape |
| Faint | Tinted white | 6 | L | Top cape |
| Faint | Tinted colour one | 7 | M | Cape |
| Very light | Tinted colour one | 8 | N | Cape |
| Very light | Tinted colour two | 9 | O | Cape |
| Very light | Tinted colour two | 9 | O | Light yellow |
| Very light | Tinted colour two | 10 | P | Light yellow |
| Very light | Tinted colour three | 11 | Q | Light yellow |
| Very light | Tinted colour three | 12 | R | Yellow |
| Light | Tinted colour three | 13-20 | S-X | Yellow |
A Diamond’s Cut Unleashes Its Light
Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light.
Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond.
| A briliáns- ** | Rendhagyó - szokatlan | Átlagos - jó | Nagyon jó - kiváló | Átlagos - jó | Rendhagyó - szokatlan |
|---|---|---|---|---|---|
| korona szöge (β) | 26,9°-alatt | 27,0°-30,6°-ig | 30,7°-37,7°-ig | 37,8°-40,6°-ig | 40,7°-nál nagyobb |
| pavilon szöge (α) | 38,4°-alatt | 38,5°-39,5°-ig | 39,6°-42,2°-ig | 42,3°-43,1°-ig | 43,2°-nál nagyobb |
| tábla mérete (%) | 71%-nál nagyobb | 70%-67%-között | 66%-53%-között | 52%-51% | 50%-nál kisebb |
| korona magassága (%) | 8,5%-alatt | 9,0%-10,5%-ig | 11%-16%-ig | 16,5%-18,0%-ig | 18,5%-nál magasabb |
| rundiszt vastagsága | különösen vékony | nagyon vékony | vékony - közepes | vastag | különösen vastag (3,5%+) |
| pavilon mélysége | 39,5 %-alatt | 40%-41%-között | 41,5%-45,0%-között | 45,4%-46,5%-ig | 47,0%-nál mélyebb |
| kalett mérete (%) | .... | .... | pontszerû - 1,9%-ig | 2,0%-3,9%-ig | 4%-nál nagyobb |
| teljes mélysége | 52,9% alatt | 53,0%-55,4%-ig | 55,5%-63,9%-ig | 64,0%-66,9%-ig | 67,0%-nál magasabb |
Diamond Carat Weight Measures a Diamond’s Apparent Size
Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams.
Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its ‘points’ alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a ‘twenty-five pointer.’ Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as ‘one point oh eight carats.’
| Weight of gem | 2,5 | 2,25 | 2 | 1,75 | 1,5 | 1,25 | 1 | 0,85 | 0,75 | 0,65 | 0,5 | 0,4 | 0,33 | 0,25 | 0,2 | 0,15 | 0,1 | 0,07 | 0,05 | 0,03 | 0,02 | 0,015 | 0,01 | 0,0075 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gem diameter | 9 | 8,6 | 8,2 | 7,8 | 7,4 | 7 | 6,5 | 6,2 | 5,9 | 5,6 | 5,2 | 4,8 | 4,4 | 4,1 | 3,8 | 3,4 | 3 | 2,7 | 2,5 | 2 | 1,72 | 1,56 | 1,35 | 1,15 |
The above table is only available brilliant cut stones, and in the case of larger stones chiselled stones substantially different from the ideal show a significant difference in size.
The typical diamond shapes
01 - circle brilliant
02 - square briliant, princess
03 - drop shaped briliant
04 - heart shaped briliant
05 - emerald
06 - oval shaped briliant
07 - navett, or marquise briliant
08 - radial briliant
Small stones are usually used for decoration:
09 - scissor-stage and baguette
10 - trapezoid baguette
11 - old and new marquise cut diamonds
The light path of the briliants
01 - Too high polished, brilliant deep: some of the incoming light is reflected back through the crown bevel, so the stone can still be pretty fiery, but because of the weakness of the proporció brillancia, that is the brilliance of the stone can only be weak.
02 - Ideal and very well polished diamond: in case of light entering the stone 100% is reflected back through the crown bevel, causing fire and wonderful crisp, sparkling shine, that brilliance.
03 - Too polished flat, shallow brilliant part of the incoming light would reflect off is not significant, but has lost a stone pavilion, and such brilliant very faint, so neither fire nor glow of beauty is not. Relative the shallow rocks, however, they seem much larger than it actually weigh.
Briliants propotions
The 'registry GIA laser' in all cases the number of the GIA certificate. In addition, it may include Ideal for polishing a stone's own number, or even a more personal message.
